DENVER – Josh Outman, a left-handed reliever signed by the Braves as a free agent in January, has begun an injury-rehab assignment after missing the first half of the season with what was initially thought to be a sore shoulder during spring trianing, but was later diagnosed as thoracic outlet syndrome.

Thoracic outlet syndrome is a disorder in which blood vessels and/or nerves become compressed in the area between the collarbone and upper chest.

Outman made a relief appearance with the Gulf Coast League Braves on Friday, and will likely pitch soon at low-A Rome. There’s no timetable yet for when he might be ready to pitch in the majors.

Three other rehabbing Braves pitchers – Williams Perez and relievers Brandon Cunniff and lefty Andrew McKirahan – could be back with the big-league team before Outman. Perez (bruised foot) and Cunniff (groin) are on the 15-day disabled list and could begin minor league rehab assignments within the next week.

McKirahan is on a minor league rehab assignment and expected to rejoin the Braves July 20, the day after he completes an 80-game suspension for using performance-enhancing drugs. Because he’s a Rule 5 draft pick out of minor league options, McKirahan must be added to the 25-man roster or be offered back to the Cubs for half of the original $50,000 claiming price.